H3C S3100V2-52TP

15
Configuring the operation modes of NTP
Devices can implement clock synchronization in one of the following modes:
• Client/server mode
• Symmetric mode
• Broadcast mode
• Multicast mode
For client/server mode or symmetric mode, you need to configure only clients or symmetric-active peers.
For broadcast or multicast mode, you need to configure both servers and clients.
Operation modes and static and dynamic associations
A single device can have a maximum of 128 associations at the same time, including static associations
and dynamic associations.
• A static association refers to an association that a user has manually created by using an NTP
command.
• A dynamic association is a temporary association created by the system during operation. A
dynamic association is removed if the system fails to receive messages from it over a specific long
time.
Operation modes affect the creation of associations in the following ways:
• In client/server mode, when you execute a command to synchronize the time to a server, the system
creates a static association. The server will not create an association (static or dynamic), but will
simply respond passively upon the receipt of a message.
• In symmetric mode, static associations are created at the symmetric-active peer side, and dynamic
associations are created at the symmetric-passive peer side.
• In broadcast or multicast mode, static associations are created at the server side, and dynamic
associations are created at the client side.
Configuring NTP client/server mode
For devices working in client/server mode, perform configurations on the clients.
Follow these steps to specify an NTP server on the client:
To do… Use the command… Remarks
Enter system view system-view —
Specify an NTP server for
the device
ntp-service unicast-server { ip-address |
server-name } [ authentication-keyid keyid | priority
| source-interface interface-type interface-number |
version number ] *
Required
No NTP server is
specified by default.